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Multirange Vertical Antennas

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ANTENTOP- 03- 2003, # 004

Multirange Vertical Antennas

 

Figure 3   shows a simple design suitable for 6 - to 17-M. Antenna has the triangular shape. Special ‘sitting’ should be used for the antenna design. Vibrators are screwed in the bottom with the help of strong screws. The design has a small mutual influence for every vibrator against each other.

 

Figure 3  A triangular shape antenna design

 

 

Figure 4 shows a simple design suitable for 6 - to 30-M.  Vibrators are screwed to a strong metal angle.

 

Figure 4  A three range antenna on a  metal angle

 

 

Distances between the vibrators are 10 -30 centimeters. It is decrease the mutual influence of the vibrators to each other.

 

Antenna Adjusting: The antenna is adjusted by changing lengths of the vibrators. It is not complicated. One way is to move vibrators relatively the metal base, as it is shown in Figure 5. Do it carefully, because the vibrators have mutual influence to each other. It needs to do additional holes on to end of the vibrators for realization of the way. It is possible to do one of the vibrators. This method always gives a good result.

 

Figure 5  A three range antenna adjusting

 

 

Other way is to change lengths of the upper ends of the vibrators.  The vibrators ends made from thick copper or aluminum wire. The wire may be shortened, move in the side, as it is shown in Figure 6.  But at the way an amateur must have access to ends of the antenna.

 

A three ranges antenna for the low ranges

 

Figure 7 shows a simple design suitable for 40 - to 160-M.  Vibrators made from a copper wire in diameter 1 to 2 mm. Vibrators have length (λ/4)*1.1. Each vibrator is matched with coaxial cable with help of its own a ‘shortening ’capacitor. The shortening capacitor can have 100-pF at ranges of 6- to 17-M, 150-pF at ranges of 20- and 30-M, 200-pF at ranges of 40-80 meters, 250-pF at 160-M. The shortening capacitors should be placed in a whether- proof box.

 

Figure 8 shows another simple design suitable for 40 - to 160-M.  Vibrators made from a copper wire in diameter 1 to 2 mm.

 

 

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